After much struggle (https://community.tp-link.com/en/home/forum/topic/671468?replyId=1370914), I have added VIGI Cameras to the NVR via the physical UI and TP-Link protocol.
 

There are 4 cameras:

• One TP-Link VIGI C540V hardware version 1.0 - with firmware 2.0.1 Build 240221 Rel 58886n
• Two TP-Link VIGI C340 V2.0 Firmware 2.0.1 Build 231227 Rel.42843n
• One C300HP-4 Hardware Version 2.0 and firmware 1.0.11 Build 230411 Rel.57861n
   

All these cameras are bound to the same TP-Link ID. After adding the cameras, the C300HP-4 works fine and shows up in the NVR. However, the other three cameras don't connect to the NVR. In the Device Access, it shows "Not Connected" in the status. I tried debugging further using ping from the NVR to the cameras' IPs, and ping works fine.
 

When I look into the NVR logs, this is what I see:

1        2024-06-18 21:22:30 Main type: Information Sub type: RTSP Progress Channel No: 6
URL: rtsp://10.0.1.13:554/stream1 | rtsp://10.0.1.13:554/stream2
State: Create Channel.

2        2024-06-18 21:22:02 Main type: Information Sub type: RTSP Progress Channel No: 4
URL: rtsp://10.0.1.11:554/stream1 | rtsp://10.0.1.11:554/stream2
State: Create Channel.

3        2024-06-18 21:21:56 Main type: Information Sub type: RTSP Progress Channel No: 5
URL: rtsp://10.0.1.10:554/stream1 | rtsp://10.0.1.10:554/stream2
State: Create Channel.

4        2024-06-18 21:21:47 Main type: Exception Sub type: IP Channel Disconnection Channel No: 5
URL: rtsp://10.0.1.10:554/stream1
State: Channel Disconnect.

5        2024-06-18 21:21:45 Main type: Exception Sub type: IP Channel Disconnection Channel No: 6
URL: rtsp://10.0.1.13:554/stream1
State: Channel Disconnect.

6        2024-06-18 21:21:14 Main type: Exception Sub type: IP Channel Disconnection Channel No: 4
URL: rtsp://10.0.1.11:554/stream1
State: Channel Disconnect.

7        2024-06-18 21:20:18 Main type: Information Sub type: RTSP Progress Channel No: 6
URL: rtsp://10.0.1.13:554/stream1 | rtsp://10.0.1.13:554/stream2
State: Create Channel.

8        2024-06-18 21:20:12 Main type: Information Sub type: RTSP Progress Channel No: 5
URL: rtsp://10.0.1.10:554/stream1 | rtsp://10.0.1.10:554/stream2
State: Create Channel.

9        2024-06-18 21:20:04 Main type: Exception Sub type: IP Channel Disconnection Channel No: 5
URL: rtsp://10.0.1.10:554/stream1
State: Channel Disconnect.

Observation:

It goes through a loop where the state changes from creating a channel to channel disconnect.
 

Logs from one of the cameras:

<4>2024-06-18 21:25:51 [RTSP] Authentication pass
<4>2024-06-18 21:25:51 [RTSP] Authentication pass
<4>2024-06-18 21:25:51 [HTTP] Add a main stream, current main stream preview client count is 1
<4>2024-06-18 21:25:51 [HTTP] Add a minor stream, current minor stream preview client count is 1
<4>2024-06-18 21:25:56 [RTSP] CloseSession called, 0th in 2, client ip: 10.0.0.30
<4>2024-06-18 21:25:56 [HTTP] Delete a main stream, current main stream preview client count is 0
<4>2024-06-18 21:25:57 [RTSP] CloseSession called, 1th in 1, client ip: 10.0.0.30
<4>2024-06-18 21:25:57 [HTTP] Delete a minor stream, current minor stream preview client count is 0
<4>2024-06-18 21:25:57 [RTSP] New client accessing: 10.0.0.30 sock 39
<4>2024-06-18 21:25:57 [RTSP] Accept client with iSessionID 0
<4>2024-06-18 21:25:57 [RTSP] New client accessing: 10.0.0.30 sock 40
<4>2024-06-18 21:25:57 [RTSP] Accept client with iSessionID 1
<4>2024-06-18 21:25:57 [RTSP] Authentication pass
<4>2024-06-18 21:25:57 [RTSP] Authentication pass
<4>2024-06-18 21:25:57 [HTTP] Add a main stream, current main stream preview client count is 1
<4>2024-06-18 21:25:57 [HTTP] Add a minor stream, current minor stream preview client count is 1
<4>2024-06-18 21:26:02 [RTSP] CloseSession called, 0th in 2, client ip: 10.0.0.30
<4>2024-06-18 21:26:02 [HTTP] Delete a main stream, current main stream preview client count is 0
<4>2024-06-18 21:26:03 [RTSP] CloseSession called, 1th in 1, client ip: 10.0.0.30
<4>2024-06-18 21:26:03 [HTTP] Delete a minor stream, current minor stream preview client count is 0
<4>2024-06-18 21:26:03 [RTSP] New client accessing: 10.0.0.30 sock 39
<4>2024-06-18 21:26:03 [RTSP] Accept client with iSessionID 0
<4>2024-06-18 21:26:03 [RTSP] New client accessing: 10.0.0.30 sock 40
<4>2024-06-18 21:26:03 [RTSP] Accept client with iSessionID 1

Observation:

I couldn't get the exact timestamp, but this is what I see in the syslog of one of the cameras.
 

IPs:

All cameras are in subnet 10.0.1.1/24, and the NVR is in subnet 10.0.0.1/24.

• 10.0.0.30 - NVR
• 10.0.1.10 - Camera
• 10.0.1.11 - Camera
• 10.0.1.12 - Camera
• 10.0.1.13 - Camera
   

FYI, I rechecked the passwords, and they are all correct.

After adding all the cameras, the NVR still says 64 Mbps bandwidth is available.
I have also turned on SRTP and checked the setup. Nothing changes. Even with STRP off the same issue exists
How come only one camera works perfectly fine, whereas the other three VIGI cameras don't appear in the NVR?

Any assistance or suggestions to resolve this issue would be greatly appreciated. Thank you!